Nuclear plant back on grid after long outage

The Columbia Generating Station reconnected to the Northwest power grid Tuesday after the longest refueling outage in its history.

The Energy Northwest nuclear plant near Richland connected to the grid when it was at 20 percent power. It will take several days to ramp up to full power, producing approximately 1,150 megawatts, or enough electricity for about 1 million Washington homes.

The nuclear power plant began its refueling outage April 6, expecting to be off line for about 80 days. However, the outage also was planned as a chance to replace the plant's 26-year-old condenser.

Because of contractor delays in the condenser replacement project, the outage stretched to about 175 days. Bonneville Power Administration has estimated the net cost of the extended outage around $60 million.

However, replacing the condenser will improve efficiency and reliability of the plant, according to Energy Northwest. Replacing it cost more than $100 million.

The condenser turns steam that has flowed through the turbine back into water for re-use in the reactor.

Outages typically are planned every two years to replace a third of the reactor's fuel.